Heat dissipation device

ABSTRACT

An exemplary heat dissipation device includes mounting feet and fasteners mounted on the mounting feet. Each fastener includes a shaft and two latching portions extending outwardly from an outer circumference of an end of the shaft. Each mounting foot defines a through hole allowing extension of the end of the shaft with two second portions. Each mounting foot defines two latching recesses in a surface thereof. Each of the latching recesses defines two blocking surfaces. When the end of the shaft with the latching portion extends through the through hole and beyond the surface of a corresponding mounting foot, the shaft is rotated with respect to the through hole so as to make the latching portion be received in the latching recesses. The blocking surfaces of the latching recesses stop the latching portions rotating with respect to the through hole to escape from the corresponding mounting foot.

CROSS-REFERENCES TO RELATED APPLICATION

This application is related to U.S. patent application Ser. No. 12/765,794 filed on Apr. 22, 2010 and entitled “LOCKING DEVICE AND HEAT DISSIPATION DEVICE USING THE SAME,” and U.S. patent application Ser. No. 12/202,391 filed on Dec. 1, 2008 and entitled “LOCKING DEVICE FOR HEAT SINK.” Such co-pending U.S. patent applications are assigned to the same assignee as the instant application. The disclosure of the above-identified applications are incorporated herein by reference.

BACKGROUND

1. Technical Field

The disclosure relates to heat dissipation devices, and, more particularly, to a heat dissipation device for dissipating heat generated by an electronic component.

2. Description of Related Art

It is well known that, during operation of a computer, electronic components such as central processing units (CPUs) frequently generate large amounts of heat. The heat must be quickly removed from the electronic component to prevent it from becoming unstable or being damaged. In many or most computers, a heat dissipation device is utilized to dissipate the heat from the electronic component.

A typical heat dissipation device includes a heat sink and a plurality of fasteners for keeping the heat sink in contact with the electronic component. The heat sink includes a base and a fin unit arranged on the base. The base includes a rectangular body, and four ears extending outwards from four corners of the body. Each of the fasteners includes a head, a shaft extending coaxially downwardly from the head, and a threaded pole extending coaxially downwardly from the shaft. An annular groove is defined in a bottom end of the shaft, close to the threaded pole. In a process of mounting the fastener on the heat sink, firstly, a spring encircles the shaft of the fastener, and then the fastener with the spring extends through the ear of the base from a top to a bottom of the base. At the same time, a downward pressure is exerted on the fastener, to make the groove extend beyond a bottom face of the base. Finally, a retaining collar is received in the groove to clasp the shaft and abut the bottom face of the base.

However, the clasping of the retaining collar on the shaft of the fastener and in the groove is not always reliable since resilient fingers of the retaining collar which are elastically deformed during the assembly may be broken off from the retaining collar. In addition, when such breakage occurs, the retaining collar can no longer be reused.

What is needed, therefore, is a heat dissipation device which overcomes the above-mentioned limitations.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the disclosure can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.

FIG. 1 is a partially exploded view of a heat dissipation device in accordance with an embodiment of the disclosure.

FIG. 2 is an isometric, assembled view of the heat dissipation device of FIG. 1, viewed from a different aspect.

FIG. 3 is a partially exploded view of the heat dissipation device of FIG. 2.

FIG. 4 is an inverted view of FIG. 3.

FIG. 5 is an enlarged view of a fastener, a spring and a mounting foot of a base of the heat dissipation device of FIG. 4.

DETAILED DESCRIPTION

Referring to FIGS. 1-2, a heat dissipation device in accordance with an embodiment of the disclosure is used for dissipating heat generated by an electronic component (not labeled) mounted on a printed circuit board (not labeled). The heat dissipation device comprises a heat conductive body 10, a heat sink 20 located over the heat conductive body 10, and a plurality of fasteners 30 mounted on the heat conductive body 10. The heat sink 20 comprises a heat radiator 25 attached to a top surface of the heat conductive body 10, a fin unit 23 comprising a plurality of fins, a plurality of heat pipes 21 thermally connected to the heat conductive body 10 and extending upwardly through the fin unit 23, and a fan 27 secured to a side of the fin unit 23 via a fan holder 29. The fin unit 23, the heat conductive body 10, and the heat pipes 21 cooperatively define a receiving space 234 therearound. The heat radiator 25 is received in the receiving space 234.

Referring also to FIGS. 3-4, the heat conductive body 10 comprises a base 11 and a heat conductive block 13 attached to a bottom of the base 11. The base 11 comprises a substantially rectangular body 110, and four mounting feet 113 extending radially and outwardly from four corners of the body 110. The heat conductive body 10 defines multiple grooves (not labeled) between the base 11 and the heat conductive block 13 for receiving the heat pipes 21 therein. The fasteners 30 are disposed on the mounting feet 113, for threadedly connecting with a back plate (not labeled) located below the printed circuit board.

Referring also to FIG. 5, each of the fasteners 30 comprises a head 31, a shaft 331 extending coaxially downwardly from the head 31 and a threaded pole 333 extending coaxially downwardly from the shaft 331. Two latching portions 335 extend outwardly and oppositely from an outer circumference of the shaft 331. The two latching portions 335 are symmetrical with respect to the shaft 331; that is, the two latching portions 335 define an angle of 180 degrees therebetween. The latching portions 335 are located at a bottom end of the shaft 331, close to the threaded pole 333. Each of the latching portions 335 has a bottom face coplanar with a bottom face of the shaft 331. The latching portions 335 extend parallel to an axis (not labeled) of the shaft 331, thereby each forming a generally rectangular column. In other embodiments, each latching portion 335 has any of various other shapes, for example, a rectangular plate shape. An elastic member 34 encircles around the shaft 331. In this embodiment, the elastic member 34 is a coil spring. A diameter of the shaft 331 is larger than that of the threaded pole 333.

Each of the mounting feet 113 of the base 11 defines a through hole 115. The through hole 115 has a figure basically identical to and slightly larger than that of the bottom end of the shaft 331 with the latching portions 335. The through hole 115 comprises a central first portion 117 allowing extension of the bottom end of the shaft 331 therethrough, and two second portions 119 allowing extension of the latching portions 335 therethrough. The first portion 117 has a peripheral inner wall. Each mounting foot 113 also defines two latching recesses 121 at a bottom surface thereof. The latching recesses 121 are defined in the inner wall of the first portion 117. Each of the latching recesses 121 defines two upright blocking surfaces 122. Each latching recess 121 has an inner extremity thereof communicating with the first portion 117. The latching recesses 121 are angularly alternated with the second portions 119 around the first portion 117, and four blocks 123 are thereby defined between the latching recesses 121 and the second portions 119.

In a process of assembling each fastener 30 onto a corresponding mounting foot 113 of the base 11, the elastic member 34 encircles the shaft 331 of the fastener 30. Then the fastener 30 with the elastic member 34 extends through the through hole 115 of the corresponding mounting foot 113 from top to bottom. At the same time, a downward pressure is exerted on the fastener 30, to make top surfaces of the latching portions 335 extend beyond the bottom surface of the corresponding mounting foot 113. The shaft 331 is rotated with respect to the through hole 115 so as to make the latching portions 335 in alignment with the latching recesses 121, and then the downward pressure is released. Thereby, the elastic member 34 is compressed between the head 31 of the fastener 30 and the corresponding mounting foot 113. The top surfaces of the latching portions 335 are in tight contact with the mounting foot 113 in the latching recesses 121 due to resilient force applied by the compressed elastic member 34. The blocking surfaces 122 stop the latching portions 335 escaping from the corresponding mounting foot 113 when the fastener 30 is subjected to vibration or shock that tends to make the shaft 331 rotate with respect to the through hole 115.

In disassembly of the fastener 30 from the base 11, a downward pressure is exerted on the fastener 30, to make the top surfaces of the latching portions 335 extend beyond the bottom surface of the corresponding mounting foot 113. The shaft 331 is rotated with respect to the through hole 115 to make the latching portions 335 align with the second portions 119 of the through hole 115. Then the downward pressure is released and the fastener 30 is raised, whereby the fastener 30 is easily removed from the corresponding mounting foot 113.

Referring again to FIG. 3, the heat pipes 21 are parallel to and spaced from each other. Each of the heat pipes 21 is U-shaped, and comprises a straight evaporation section 210 and two condensation sections 212 extending upwardly from two opposite ends of the evaporation section 210. The evaporation sections 210 of the heat pipes 21 are received in the grooves defined between the base 11 and the heat conductive block 13. The two opposite ends of each of the evaporation sections 210 extend beyond two corresponding lateral sides of the body 110 of the base 11.

The fin unit 23 comprises a plurality of fins 230. The fins 230 are parallel to and spaced from each other, and are parallel to the base 11. An air passage 232 is defined between each two adjacent fins 230. The fins 230 are connected with top portions of the condensation sections 212 of the heat pipes 21. A wind-guiding cover 26 is disposed between the heat radiator 25 and the fin unit 23. The wind guiding cover 26 comprises an aslant wind guiding plate 261 guiding airflow generated by the fan 27 to a circumference of the electronic component. The wind guiding plate 261 slants downwardly and outwardly from a bottom fin 230 of the fin unit 23.

It is to be understood, however, that even though numerous characteristics and advantages of various embodiments have been set forth in the foregoing description, together with details of the structures and functions of the embodiments, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the disclosure to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed. 

1. A heat dissipation device comprising: a heat conductive body comprising a plurality of mounting feet extending outwardly therefrom; and a plurality of fasteners mounted on the mounting feet, each of the fasteners comprising a shaft, an elastic member encircling the shaft, and two latching portions extending outwardly from an outer circumference of an end of the shaft; wherein each of the mounting feet defines a through hole comprising a central first portion allowing extension of the end of the shaft therethrough and two second portions allowing extension of the latching portions therethrough, each mounting foot defining two latching recesses in a bottom surface thereof, each of the latching recesses bounded by two blocking surfaces; wherein when the end of the shaft with the latching portions of each fastener extends through the through hole and beyond the bottom surface of a corresponding mounting foot, and the shaft is then rotated with respect to the through hole so as to cause the latching portions to be received in the latching recesses and held therein by the elastic member, the blocking surfaces of the latching recesses stop the latching portions from rotating with respect to the through hole and disengaging from the mounting foot.
 2. The heat dissipation device of claim 1, wherein the latching recesses each have an inner extremity thereof communicating with the first portion of the through hole.
 3. The heat dissipation device of claim 1, wherein the first portion of each mounting foot has a peripheral inner wall, the latching recesses being defined in the inner wall of the first portion.
 4. The heat dissipation device of claim 1, wherein the latching portions extend oppositely from the outer circumference of the end of the shaft.
 5. The heat dissipation device of claim 1, wherein the latching recesses are radially alternated with the second portions of the through hole around the first portion, four blocks thereby being defined between the latching recesses and the second portions.
 6. The heat dissipation device of claim 1, wherein the latching portion has a bottom surface coplanar with a corresponding bottom face of the shaft.
 7. The heat dissipation device of claim 1, wherein each of the fasteners further comprises a head located at an opposite end of the shaft, the elastic member being compressed between the head and the corresponding mounting foot.
 8. The heat dissipation device of claim 1, wherein each of the fasteners further comprises a threaded pole extending downwards from the end of the shaft, a diameter of the threaded pole being smaller than that of the shaft.
 9. The heat dissipation device of claim 1, wherein the latching portions each have a columnar configuration parallel to an axis of the shaft.
 10. The heat dissipation device of claim 1, wherein the heat conductive body comprises a base and a heat conductive block coupled to a bottom of the base, the mounting feet extending radially outwardly from the base.
 11. The heat dissipation device of claim 1, further comprising a heat sink located over the heat conductive body, wherein the heat sink comprises a fin unit and a plurality of heat pipes thermally connected to the heat conductive body and extending through the fin unit.
 12. The heat dissipation device of claim 11, further comprising a heat radiator, which is located between the fin unit and the heat conductive body.
 13. The heat dissipation device of claim 11, wherein the heat sink further comprises a fan and a fan holder, the fan holder secures the fan to a lateral side of the fin unit, the fin unit defining a plurality of air passages, and the fan is positioned such that airflow generated by the fan can flow through the air passages of the fin unit.
 14. The heat dissipation device of claim 13, wherein the heat sink further comprises a wind guiding plate slanting downwardly and outwardly from a bottom fin of the fin unit for guiding the air flow generated by the fan to a circumference of the heat dissipation device.
 15. The heat dissipation device of claim 13, wherein the elastic member is a coil spring.
 16. A heat dissipation device comprising: a heat conductive body comprising a main portion and a plurality of mounting feet extending outwardly from the main portion; and a plurality of fasteners mounted on the mounting feet, each of the fasteners comprising a shaft, an elastic member encircling the shaft, and a latching portion extending outwardly from an outer circumference of an end of the shaft; wherein each of the mounting feet defines a through hole comprising a central first portion allowing extension of the end of the shaft therethrough and a second portion allowing extension of the latching portion therethrough, each mounting foot defining a latching recess in a bottom surface thereof, the latching recess bounded by two blocking surfaces; wherein when the end of the shaft with the latching portion of each fastener extends through the through hole and beyond the bottom surface of a corresponding mounting foot, and the shaft is then rotated with respect to the through hole so as to cause the latching portion to be received in the latching recess and held therein by the elastic member, the blocking surfaces of the latching recess stop the latching portion from rotating with respect to the through hole and disengaging from the mounting foot.
 17. The heat dissipation device of claim 16, wherein the latching recess has an inner extremity thereof communicating with the first portion of the through hole.
 18. The heat dissipation device of claim 16, wherein the first portion of each mounting foot has a peripheral inner wall, the latching recess being defined in the inner wall of the first portion. 